Silicon-based magnetic sensors generally use the asymmetry induced by the magnetic field based upon the Hall effect. This is because, after a magnetic field has been applied, an electric field is created perpendicular to the electric current causing a shift in the lines of current. A potential difference then occurs that can be measured, and this difference is proportional to the magnetic field and to the electric current.
In the microelectronics field, the trend towards components of increasingly small dimensions means an undesirable reduction in the sensitivity of sensors of this type. To overcome this drawback, it is either necessary to use a low operating temperature or a material having a high electron mobility. The use of a low temperature makes it more difficult to use sensors, and increases the complexity and cost of the magnetic-field measurement devices. Furthermore, silicon, which is a material of choice in microelectronics, has a relatively low electron mobility (1500 cm2/Vs at room temperature), which impedes its use in Hall-effect sensors.